This is a library of perfboard and single-sided PCB effect layouts for guitar and bass. I'm not an electrical engineer by any stretch of the imagination, just a DIY'er who likes drawing layouts. It is meant for the hobbyist (so commercial use of any of these layout is not allowed without permission) and as a way to give back to the online DIY community.

Friday, January 13, 2017

Earthquaker Devices Bellows

For Fuzz Friday here's the Bellows from Earthquaker. I picked up one of these late last year and was able to trace it. It's fairly simple but sounds really good. It's really similar to an Electra circuit, but with a JFET going between the base and collector of the transistor. Here's the schematic for reference.


In the originals the resistors are large carbon comp and all caps are film box types (with the exception of C3). I breadboarded this with mostly metal film resistors and with whatever caps were closest, along with a J201 for the JFET and it sounded very much like the original. 



Here's a few pics of the original guts, btw. A lot of the circuitry on the board is for the relay bypass (that I did not trace as it would be mostly pointless with out the code for the PIC).

 

28 comments:

  1. I had a feeling this one was coming for Fuzz Friday! Can't wait to give this a try. And totally surprised that the circuit looks like this, I imagined something way for complex.

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  2. First thanks for helping the community and a great work, just curiosity in the circuit seemed to have an opamp smd something of the genre what was the function?

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    1. That IC is a PIC that's part of the relay bypass switching. Because the effect circuit is so simple, the majority of the components on the board are for the bypass.

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    2. Got it. Yes thats so simple and sounds great. I will breadboard today. Thank you!

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  3. Sounds beautiful and furious... I'll put this one in my setup...

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  4. Maybe I missed it but I can't find this in the Image Transfer Library.

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    1. Must have forgotten to upload it. It's in the Earthquaker folder now.

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  5. My next project!!! Thanks for the info.

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  6. Great effect, thanks for all your work!!! I've added a BMP Tonestack to have a control tone.

    Thanks a lot!!!

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  7. Maybe a 2N5457 can work great too

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  8. Seems like fet would be MPf 102, l made a breadboard layout with diy LC becuase iwas bored and not any home with access to gear. Can yall take a look and tell me if its correct. I went with j201 fet pin out

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  9. It's ok if I use a 1N400x instead of the 5817 one for that position?
    Thanks

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    1. Yes. I'll just lower the supply voltage just a little bit more than the 5817. Not that big a deal though.

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    2. Thanks
      a 1n4007 to be exact. I have 1N60, and bzx79b.
      Which one you consider the best one?

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  10. Done!

    I used 2N5457, and 1N4007 if anyone are looking for replacements.
    This thing is loud!

    Thanks..!

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    Replies
    1. Yes.!
      Used sockets and tried J201, and BF245 too.

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  11. Would it be a benefit to use LOG pots instead of linear?

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    1. In the original I have linear taper seemed fine. In the clone I built I think I used an A250k for the gain control and it also seemed fine. YMMV

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  12. This might be a dumb question, but why is the 5817 and 100uf cap in the layout not a part of the circuit? What purpose does that serve?

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    1. Not a part of the schematic*

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    2. Because they're for power filter cap and added polarity protection. Optional, and highly recommended

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  13. This comment has been removed by the author.

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    1. This comment has been removed by the author.

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  14. Hi, i just built it, and it works, but the pedal doesn't sound like the one in the video test, it sounds much like a classic fuzz, without the extra dirty growl it should have. It sounds great, but notre the sound I was expected. Could it be hfe values? I i used same transistors as the original circuit. Thanks

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